1. Field of the Invention
The present invention relates to a ball screw device or a linear motion guide device having a bearing failure monitoring device, and more particularly to a ball screw device or a linear motion guide device having a bearing failure monitoring device for sensing or detecting a wear or failure of the ball bearing members and for generating a warning signal.
2. Description of the Prior Art
Typical ball screw devices or linear motion guide devices comprise a ball nut or sliding member slidably attached or mounted onto an elongated member or screw shaft, and having helical ball guiding passages formed therein for forming or defining an endless multiple-turn, helical raceway therein, and a number of ball bearing members engaged in the endless multiple-turn, helical raceway for facilitating the sliding movement between the elongated member or screw shaft and the ball nut or sliding member.
Normally, the elongated member or screw shaft and the ball nut or sliding member may be slid or moved in a great speed relative to each other, and the ball bearing members may have a good chance to become wear or failure after use, and the typical ball screw devices or linear motion guide devices may also become failure after use.
For example, U.S. Pat. No. 7,523,682 to Liao et al. discloses one of the typical linear motion guide devices including an arrangement for smoothly guiding two sliding members to slide relative to each other. However, Liao et al. failed to teach an integrated circuit disposed for detecting a moving frequency between the two sliding members, particularly when the typical linear motion guide devices have become wear or damaged or failure after use.
U.S. Pat. No. 4,414,863 to Heino, and U.S. Pat. No. 7,299,703 to Balasu et al. disclose the other typical bearing balls escape and wear annunciator arrangements for ball screws including an arrangement for detecting a load bearing failure and including a pair of electrical sensors installed on a load path that is threadedly engaged with the screw shaft, and the electrical sensors are required to be engaged into the helical threaded portions or grooves of the screw shaft in order to detect the load bearing failure.
However, it will be difficult to install or dispose or attach or mount the electrical sensors into the load path, and the electrical sensors may not be used to suitably or effectively sense or detect the wear or failure of the ball bearing members due to the filling or engagement of the grease or lubricating oil in the endless multiple-turn, helical raceway that receives the ball bearing members.
U.S. Patent Publication No. 2006/0045406 to Iwamoto et al. discloses a further typical linear motion guide device including a detecting device having a magnetic member and an integrated circuit disposed for detecting a moving frequency that communicates with nearby component for the purposes of installing sensors compactly in a bearing assembly while detecting the target component in a stable manner.
Actually, in Iwamoto et al., a sensor-equipped wheel support bearing assembly is disclosed and includes rotation sensors installed in compact in the bearing assembly for detecting, in a stable fashion, the number of revolutions of the vehicle wheel and the load acting on the vehicle wheel.
However, in Iwamoto et al., the rotation sensors are installed in the bearing assembly for detecting the number of revolutions of the vehicle wheel and the load acting on the vehicle wheel, and a number of displacement sensor assemblies are further required and disposed at respective locations circumferentially equidistantly spaced from each other, and the rotation sensor is positioned between the displacement sensors for detecting the number of revolutions of the vehicle wheel and the load acting on the vehicle wheel, but may not be used for detecting whether the typical linear motion guide device has become failure or not.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional bearing failure monitoring devices for ball screw devices or linear motion guide devices.